I know I’m not the person who this question was directed towards, but I figured I’d give a shot at answering this, if that’s okay.
Photoshop will always be an amazing tool for a variety of purposes, but it is surprisingly helpful in creating simple game textures. There’s a great article that explains some techniques, but I’m hesitant to link it. So, here’s a summary with some of my own pointers thrown in:
Although Filters are oftentimes looked down upon, they can be manipulated and combined to create more intricate results. For example, combining the Noise and Emboss filters can give you a base for a customized concrete texture. Similarly, we can create a wood texture by “squashing” a rendered cloud filter in half via the Image Size tool and then adding the Posterize effect, producing the beginnings of a sweet wood grain.
Use Blending Modes to combine layers. Try breaking down an otherwise complex texture into layers and combining them through blending. There’s also Advanced Blending and Blend If options that can be used to only affect certain portions of your texture. For example, you can create a glossy texture by only affecting white painted areas.
Combine gradients, solid colors, etc. Adding on to the previous points, having your levels/areas of detail separated between layers helps both in organization and just seeing what you’re doing to the texture. An example provided in the article is a wine bottle that uses 3 different gradient shadow textures: one for the general color and shading, one of the edges, and one for the bulb shape that you often see at the bottom of a wine bottle.
Use Brushes, both built in and customized. These can be used to do whatever you want, from adding dirt to a texture to putting “dents” in a metal frame. It’s a slightly complicated process, though can result in some amazing textures!
Add color at the end! If you’re making something from scratch, color will just get in the way of your texturing process. There are exceptions to this (like with brushes), but use your own judgement.
Bonus round: Just use existing images that you can then modify! If you don’t have the time or knowledge to create custom textures from scratch (I know I don’t, most of the time), use textures from existing pictures or scans. However, be careful with incorrect perspective, lighting, and the chance of making the texture appear “flat”.
Additionally, 3ds Max is an amazing tool, but it’s pretty dang expensive. Sometimes I just use Paint . NET (separated so that it does not create a link), but it’s pretty janky and limited in comparison to Photoshop. The caveat to all of this is that most of the time I personally just look for something online, because by no means am I a full-time, professional dev and thus the results are not worth the time spent.
Hope this helps a bit! It’s kind of a crazy process, so if someone else has an easier way to make textures from scratch, I’d love to hear about it so I don’t have to spend hours slaving away for exactly what I’m looking for.